Office Christmas Party offers up the craziest holiday bash of the year, subverting and perverting the corporate Yuletide mixer in myriad ways. The unruly workplace comedy — which features Jennifer Aniston, T.J. Miller, Jason Bateman, Courtney B. Vance, Olivia Munn, Kate McKinnon, Randall Park, Jillian Bell, Vanessa Bayer, and Sam Richardson, among others — throws all the HR-enforced rules (along with a vending machine or two) out the window, all in the name of impressing a client who appears to be the key to saving the company from painful layoffs. It also features a rivalry between the icy-dispositioned interim CEO Carol (Aniston), who is mandating the cuts, and the people-first Chicago branch president (Miller), who happen to be brother and sister. A brother and sister whose fiscal fights sometimes devolve into score-settling wrestling matches.

Given that this is the season for family and traditions, we asked Aniston, Miller, Vance, and Munn — who grace this week’s cover of EW — to recall their family’s weird holiday traditions. Aniston’s answer just might take the cake (and may also explain her smooth moves in Just Go With It).

JENNIFER ANISTON: “When I was a kid, they used to make me belly dance. On Christmas Eve. My dad’s whole side of the family is Greek, so I would dress up as a little Greek girl and then on Christmas, after taking belly-dancing classes, I would do that. It had nothing to do with Christmas, even. It was just, ‘Let’s humiliate Jen on Christmas.'”

T.J. MILLER: “We have a Thanksgiving tradition where my mother has everybody go around and say what they’re thankful for. Growing up, I thought that was such a brilliant idea. As an adult, I now understand how uncomfortable it makes the guests who are not related.”

COURTNEY B. VANCE: “We used to get our Christmas tree on Christmas Eve. [We kids] thought it was just fun to do, and we used to go at midnight. But as we got older, we found out that the trees were cheaper — you can get them for a dollar. [Our parents] didn’t have a lot of money, but they made us think it was just a wonderful tradition.”

OLIVIA MUNN: “I like to play a game called Let’s All Go Around the Table and Say One Thing That We Would Change About the Person on Our Left, and I like to go first. Really, the most fun games to play as a family are the emotional ones. It definitely doesn’t feel like family unless someone is trying to hurt your feelings.”

To read more on Office Christmas Party, out Dec. 9, pick up the new issue of Entertainment Weekly on stands now, or buy it here now – and subscribe for more exclusive interviews and photos, only in EW.